1. Technical Field
The present invention relates to a technical field of, for example, an electro-optical device substrate and a method of manufacturing the same, used for an electro-optical device such as a liquid crystal device, an electro-optical device provided with the electro-optical device substrate, and an electronic apparatus, such as a liquid crystal projector, for example, provided with the electro-optical device.
2. Related Art
A liquid crystal device, which is an example of the above electro-optical device, is not only used for a direct view type display but also used widely, for example, as a light modulating device (light valve) of a projection-type display device. Particularly, when in a projection-type display device, because intensive light emitted from a light source enters a liquid light valve, a light shielding film, which serves as a light shielding device that blocks incident light, is installed in the liquid light valve so that a thin-film transistor (TFT) in the liquid light valve does not cause an increase in leakage current and/or a malfunction, or the like, because of the intensive light. In regard to the above light shielding device or the light shielding film, Japanese Unexamined Patent Application Publication No. 2004-4722 describes a technology for blocking light using a scanning line, which serves as a gate electrode, in a channel region of a TFT. Japanese Patent No. 3731447 describes that light that reaches a channel region of a TFT is reduced by providing a plurality of light shielding films formed on the channel region and a layer that absorbs internally reflected light. Japanese Unexamined Patent Application Publication No. 2003-262888 describes a technology for reducing incident light that enters a channel region of a TFT as much as possible while making it possible to ensure an appropriate operation of the TFT and to reduce the width of a scanning line.
However, when light is irradiated to a junction region, such as an LDD (Lightly Doped Drain) region, for example, formed between a channel region and a source/drain region, there is a problem that light leakage current may occur in the junction region. To deal with the above problem, it is conceivable that a light shielding device is provided on or above junction regions on both sides of the channel region, but, in view of display performance, it is undesirable to reduce an aperture region in each pixel through which light is substantially transmitted. On one hand, the inventors of this application have estimated that light leakage current tends to occur in the TFT more easily when light is irradiated to a junction region formed between a source/drain region, connected to a pixel electrode, and the channel region than when light is irradiated to a junction region formed between a source/drain region, connected to a data line, and the channel region.
On the other hand, in an electro-optical device of this type, there is a need for miniaturization of pixels in order to implement a small-sized device and a high-definition display image.